Pneumatic tire

Abstract

A pneumatic tire includes at least one carcass layer between bead portions on an inner side in a radial direction of sidewall portions on both sides of a tread portion extending in a circumferential direction and having an annular shape, and the carcass layer includes carcass cords formed of organic fiber cords obtained by intertwining a filament bundle of organic fibers. The carcass layer includes turn-up portions formed by being turned back at an end portion of the bead portions to an outer side in a tire width direction. The carcass cords have an elongation at break EB satisfying EB≥15%, a cap tread rubber compound of the tread portion has a 300% modulus MD satisfying 4 MPa≤MD≤13 MPa, and the elongation at break EB and the 300% modulus MD satisfy 600≤40×MD+20×EB (%)≤1300.

1 - 5 . (canceled) 
     
     
         6 . A pneumatic tire comprising:
 a tread portion extending in a tire circumferential direction and having an annular shape;   a pair of sidewall portions respectively disposed on both sides of the tread portion;   a pair of bead portions each disposed on an inner side of the sidewall portion in a tire radial direction; and   at least one carcass layer spanning between the pair of bead portions,   the carcass layer comprising carcass cords formed of organic fiber cords obtained by intertwining a bundle of filaments of organic fibers, and comprising turn-up portions respectively formed by being turned back at an end portion of the pair of bead portions to an outer side in a tire width direction,   the carcass cord having an elongation at break EB of 15% or more, a cap tread rubber compound of the tread portion having a 300% modulus MD of 4 MPa≤MD≤13 MPa, and the elongation at break EB and the 300% modulus MD being such that 600≤40×MD+20×EB (%)≤1300.   
     
     
         7 . The pneumatic tire according to  claim 6 , further comprising:
 a plurality of belt layers disposed on an outer side of the carcass layer in the tire radial direction, wherein   the tread portion comprises a pair of center main grooves extending in the tire circumferential direction with a tire equator line interposed between the center main grooves, and a center land portion defined by the pair of center main grooves, and   the center land portion located within 10% of a width of a second widest belt of the belt layers on each of a left side and a right side of a tire equatorial plane in the tire width direction has an average total gauge GC satisfying 5 mm≤GC≤10 mm, and   the average total gauge GC, the 300% modulus MD, and the elongation at break EB are such that 1100≤60×GC+40×MD+20×EB (%)≤1600.   
     
     
         8 . The pneumatic tire according to  claim 6 , wherein
 the carcass cords have, under a load of 1.0 cN/dtex, an intermediate elongation EM satisfying EM≤5.0%.   
     
     
         9 . The pneumatic tire according to  claim 6 , wherein
 the carcass cords have a standard amount fineness CF satisfying 4000 dtex≤CF≤8000 dtex.   
     
     
         10 . The pneumatic tire according to  claim 6 , wherein
 the carcass cords have, after dip treatment, a twist coefficient CT satisfying CT≥2000 (T/dm)×dtex 0.5 .   
     
     
         11 . The pneumatic tire according to  claim 7 , wherein
 the carcass cords have, under a load of 1.0 cN/dtex, an intermediate elongation EM satisfying EM≤5.0%.   
     
     
         12 . The pneumatic tire according to  claim 11 , wherein
 the carcass cords have a standard amount fineness CF satisfying 4000 dtex≤CF≤8000 dtex.   
     
     
         13 . The pneumatic tire according to  claim 12 , wherein
 the carcass cords have, after dip treatment, a twist coefficient CT satisfying CT≥2000 (T/dm)×dtex 0.5 .